Using Fiber Reinforced Concrete to Control Early-Age Shrinkage in Replacement Concrete Pavement

Abstract

Unlike ordinary concrete pavement, replacement concrete pavement needs to be open to traffic within 24 h (sooner in some cases). Thus, high early-strength concrete is used; however, it frequently cracks prematurely as a result of high heat of hydration that leads the slab to develop plastic shrinkage. FRC is known to provide good resistance to plastic shrinkage. This paper explores the potential use of fiber- reinforced concrete (FRC) in concrete pavement replacement particularly in controlling plastic shrinkage. Five different fiber types, including steel, glass, basalt, nylon, and polyethylene fibers were investigated. Additionally, the effect of fiber length was also investigated for the polyethylene fiber. The fibers were added at low dosage amounts of 0.1% and 0.3% by volume. A retrained shrinkage test was conducted to assess the cracking potential of the concrete mixtures and the ability for each fiber type to resist cracking. Results indicated that both polyethylene and nylon fibers provided the best resistance to early-age shrinkage. Short fibers (<1-in.) also had the best performance in resisting early-age shrinkage, while long fibers (>1-in.) provided additional post-cracking capacity. For replacement concrete pavement, it is recommended that a short polyethylene fiber be used to eliminate uncontrolled cracking.